Transformer-lead.



PATENTED JUNE 13, 1905.

J. J. FRANK.

TRANSFORMER LEAD.

APPLIOATIOK nun nov. 16, 1904.

Fig.4.

5 E .5 S E N W W INVENTOR dcl'm J. Frank,

n .Q -v-l flmz Eatenteo June 13, 1905.

JOHN J. FRANK, OF SCHENEGTADY, NEW

ELECTRIC COMPANY,

A CORPORATION OF NEW YORK, ASSIGNOR TO GENERAL YORK.

TRANSFORMER-LEAD.

SPECIFICATION forming part of Letters Patent No, 792,016, dated June 13,1905.

Application filed November 16, 1904. Serial No, 232,942.

To (0U whom, it Duty 0 (HY/C6777! J. FRANK, a citizen of the UnitedStates, residing at Schenectady,

county of Schenectady, have invented certain ments in Transformcr-Llowing is a specification new and State of New York,

useful Improveeads, of which the fol- I Modern transformers,particularly highvoltage transformers, are ordinarily immersed in oilcontained in metal casings. Heretofore much difficulty has beenexperienced with high-voltage transformers of this character ininsulating the transformer-leads from the 011- containing metallic casiof which they overcome these difficulti licient and conductors ngsthrough the walls must necessarily be passed. To

es and to obtain a sufproper insulation for the terminal of high-voltagetransformers, I

have devised the construction hereinafter described and illustrated.

The various features of novelty which characterize my invention Iparticularity forming a part of this have pointed out with in the claimsannexed to and specification. For a better understanding of theinvention, however, reference may be had to the accompanying drawings,in which" Figure 1 is an elevati on, with parts broken away and insection, showing a portion of a transformer-casing through which passesa transformer lead. or conductor and its bushing. Fig. 2 is anelevation, with parts broken away and in section.

struction. Fig. 3 is a sec showing a modified contional elevationshowing another construction of the bushing, and

Fig. 4 is an elevation sh struction.

In the drawings, 1 re the wall of a casing in owing a detail ofconpresents a portion of which an oil-cooled and insulatedhigh-potential transformer is loof as at oated. The cover 2 with anaperture,

transformer terminal leads 4 pass.

the casing is formed 3, through which the Referring particularly to theconstruction shown in Fig.

1, a conductor 5 with threaded ends. rounds the conductor concentrictherewith, is tion to the conductor by is shown in the form of a rodbushing 7, which surand is substantially secured in fixed relaclampingmembers 8,

l l l I l formed of metal, and nuts 9, secured on the threaded ends ofthe conductor. The bushing isformed of a number of similar rings orannular members 10, of suitable insulatingmaterialsuch as wood,wood-pulp, pressed board, oiled linen, glass, porcelain, or thelikewhich are formed each with a cylindrical inner tongue or flangeportion 11, projecting from the inner side of the body of the ring, anda concentric cylindrical tongue or flange portion 12, projecting fromthe outer side of the opposite end of the body portion of the ring.These rings are assembled so that the adjacent inner and Outer flangesof the adjacentrings or sections overlap. As shown, the outer flangeportion 12 of each section is shorter than the inner flange portion 11.As a result a circumferential space or groove is formed between theouter surface of each pair of adjacent rings 10, in which is placed anannular washer member or barrier 13, formed of suitable insulatingmaterial, such as pressed board or the like. As shown, the two rings ormembers 10 adjacent to the middle ring of the bushing eX- tend outwardto form collars or flanges 14, between which the annular member 15,which may be formed of marble or the like, is secured. The marble inturn is then secured to an annular member 16, formed of metal. Themember 16 is secured to the casing-cover by bolts 17. A bottom member 18for the bushing may be secured to the lower end. of the conductor by anut 19. The bottom member 18 is formed with an inner flange portion 11,which overlaps the outer flange portion of the adjacent ring. Adrain-plug 18 may be employed in the bottom member 18, as shown. Afterthe rings or sections and annular members are secured together betweenthe end members by the conductor 5 the whole is treated in any suitablemanner, as by dipping in suitable varnish or other insulating liquid, toincrease the insulating properties of the bushing and to fill all thecrevices and spaces between difl'erent adjacent cylindrical members anddisks, thus eliminating any joints in surface of the bushing andobtaining an oil-tight vessel. The space within the bushing surroundingthe conductor is then filled with a suitable insulating material, whichmay be liquid at ordinary temperatures, such as a suitable oil, or maybe a solid at ordinary tem by an annular washer or member 23, whichmaybe formed out of wood'or the like.

The construction employed insures a very high degree of insulationbetween the conductor and the casing. The annular members 13 or barriersserve to interrupt the continuity of a brush-discharge occurring alongthe outer surface of the bushing and lessen the liability of and effectsproduced by such discharges? The ring-sections 10 when of wood should beso formed that the grain of the wood does not extend parallel to theaxis of the bushing, as the insulating properties of wood in thedirection of its grain are much less marked than those across the grainof the wood. The construction heretofore described is much less apt tobe distorted by warping or the like than would be the case if the Woodenrings or sections were integrally connected.

To still further increase the insulation about the conductors, Isometimes prefer to surround the rod by tubular members 5, preferably ofinsulating material, to subdivide the oil into a number of separate andindependent ducts.

In some cases it is desirable to employ a certain amount of reactance inseries with the terminal conductors or transformers to protect thetransformer against the high-frequency discharges. In Fig. 2 I haveshown a construction in which this reactance is located within theinsulating-bushing. In the construction shown in Fig. 2 a rod 24, ofinsulating material, has secured to its end threaded rods of conductingmaterial 25. The bushing is held together by nuts on the rods 25 in thesame manner as the bushing first described is held together by nuts onthe end of the conductor 5. A conductor 5" in the form of a helixsurrounds the rod 24, the adjacent turns of which do not touch eachother, and has its ends secured to the rods 25. The conductor 5 thusserves to connect the rods 25 and furnish the necessary reactance.Preferably the internal diameter of the helix is such that the helicalconductor does not touch the rod of insulating material. With thisconstruction I am able to place the proper amount of reactance toprotect the terminal in a very desirable location. Should the strain onthe transformer be great enough to cause an are between the adjacentturns of the helical conductor, the are formed will be immediatelyextinguished by the oil in the bushing.

In Fig. 3 I have shown a construction in which the body of aninsulating-bushing is formed of an inner cylindrical portion 26,

which may consist of a number of layers of oiled linen or similarfabric. Annular members 13 are strung on this cylinder and are separatedfrom each other by collar portions or cylinders 27 also formed of anumber of layers of oiled linen or similar fabric of insulatingmaterial. The linen forming the walls of the bushing in this case isimpregnated with oil of such a character that when the bushing istreated in a proper manner the layers will weld together to destroy alljoints or surfaces between adjacent layers and also between the ends ofthe collar portions and the annular members.

I may dispense with an end member, as the member 18, for closing thelower end of the bushing where it is desired to entirely fill the casingand bushing with oil, in which case it will of course be understood thatthe joints between the case and cover and in the cover should beoil-tight.

While I have hereinbefore described and illustrated the best form of myinvention now known to me, I do not wish the claims herein made to belimited to the particular construction shown other than is madenecessary by the state of the art.

It will be obvious to those skilled in the art that the constructiondescribed can be used for other purposes than that specified.

What 1 claim as new, and desire to secure by Letters Patent of theUnited States, is

1. An insulating-bushing formed of annular members of insulatingmaterial, each comprising an inner flanged portion and an outer flangedportion, the inner and outer flanged portions of adjacent membersoverlapping, and a washer or member secured between an adjacent pair ofsaid annular members.

2. An insulating-bushing formed of a number of similar interlockingannular members made of insulating material, and washers located onebetween each adjacent pair of said members.

3. An insulating-bushing formed of a number of annular members, eachprovided with an inner flanged portion and an outer flanged portion,arranged with the inner and outer flanged portions of adjacent membersoverlapping, and a rod or bar within said bushing for securing the endmembers of said bushing together. a

4:. An insulating-bushing formed of a number of annular members, eachcomprising an inner flanged portion and an outer flanged portion, theinner and outer flanged portions of adjacent members overlapping, andwashers secured one between each adjacent pair of members.

5. A bushing formed of a number of annular members, each provided withan inner flanged portion and an outer flanged portion,

such

and washers placed one on the inner flanged portion of each member, saidmembers being arranged with the inner and outer flanged portions ofadjacent members overlapping.

6. In combination, a metallic casing formed with an aperture, a bushingof insulatingmaterial passing through said aperture, and a conductoraxially located in said bushing and separated from the walls thereof byan insulating liquid.

7. In combination, a casing formed with an aperture, a bushing ofinsulating material passing through said aperture, and a conductoraxially located in said bushing and separated therefrom by insulatingmaterial inserted in said bushing in the form of a liquid.

8. In combination, a metallic easing formed with an aperture, a bushingpassing through said aperture, and a conductor axially located in saidbushing and separated therefrom by liquid insulating material.

9. An insulating-bushing, a number of similar interlocking annularmembers made of insulating material, and means located within saidbushing for securing said members together.

10. The method of forminga bushing which consists in forming acylindrical body portion surrounded by separate washer members locatedat intervals along said body portion, and

then treating the same to destroy all fissures in the surface thereof.

11. In combination, a bushing formed of insulating material, conductorsextendinginto the ends of said bushing, means within the bushing forengaging the ends of said conductors and securing them and the bushingin fixed relation, and a reactance located within the bushing and havingits terminals connected to said conductors.

12. In combination, a bushing formed of a number of annular members ofinsulating material, conductors engaging the end members of saidbushing, and means passing through said bushing for mechanicallyconnecting said conductors.

13. In combination, a bushing formed of a number of annular members ofinsulating material, conductors engaging the end members of saidbushing, means passing through said bushing for mechanically connectingsaid conductors, and a helical conductor within said bushing having itsends connected to the firstmentioned conductors.

14. An insulating-bushing formed of similar interlocking annular membersof insulating material, and a surface-increasing washer member locatedbetween an adjacent pair of said annular members.

In witness whereof I have hereunto set my hand this 14th day ofNovember, 1904.

JOHN J. FRANK.

WVitnesses:

BENJAMIN B. HULL, HELEN ORFORD.

